5 Paediatrics, TYKS Turku University Hospital, Turku, Finland.
6 Department of Pediatrics, Tromso University Hospital, Tromso, Norway.
7 Department of Paediatrics and Adolescent Medicine, University of Copenhagen, Institute of Clinical Medicine, Faculty of Health and Medical Sciences, Copenhagen University Hospital, Kobenhavn, Denmark.
8 Institute for Public Health, Aarhus Universitet, Research Unit for General Practice, Aarhus, Denmark.